If you've ever felt like your MD brushed off your concerns, but that the problem wasn't in fact in your head, you may be suffering from one of these often overlooked conditions.

Sleep apnea

Sleep apnea

Fighting low energy is a normal part of a busy life, right? Not always. When fatigue becomes chronic, it may be a sign of a lurking health disorder. "As women, we tend to brush off our symptoms, thinking they may be from overextending ourselves or taking on too much, but this may not be the case," says Dr. Lauren Weber, a physician at the Cleveland Clinic's Center for Specialized Women's Health. Depression, hypothyroidism, vitamin-D deficiency, diabetes, and sleep apnea are among the issues Dr. Weber says could be the underlying reason for your fatigue. Sleep apnea is particularly common and worrisome because if left untreated, it can increase your risk for hypertension, stroke, and even heart attack. Focus on good sleep habits — like keeping the same bedtime every night and not watching TV in bed — and eat a well-balanced diet to combat fatigue. If you're still falling asleep at your desk or behind the wheel, it's a good idea to get tested for sleep apnea via a sleep study.

Perimenopause or menopause

Perimenopause or menopause

Hot flashes, night sweats, decreased sex drive — women might feel that these less-than-pleasant symptoms of perimenopause and menopause are just something that they have to cope with. But, that's not necessary, says Dr. Weber, who advises starting treatment as soon as possible. "The best time to get treated is within the first 10 years of menopause; there is actually a decreased cardiovascular risk associated with starting hormone therapy, which is the best treatment for moderate to severe menopause symptoms," says Dr. Weber. And if you needed another reason to quit — smokers are at higher risk for early menopause.